It is known that the two laser beams in a ring laser gyro will lock on to each other if their frequency difference is too low, a condition that can occur at low input (rotation) rates, rendering the gyro (RLG) unable to detect low angular input rates. To eliminate this problem, a gyro can be mechanically modulated ("dithered") a small amount by a dither motor.
An electric motor drive, such as a piezoelectric transducer operating on a torsion spring to which the gyro is mounted, may be used to dither the gyro and a similar transducer (dither pickoff) can be attached to the gyro to detect the dither motion as part of closed loop dither control to sustain spring oscillation at a desired amplitude that does not interfere with gyro operation.
In practice, however, the level of the signal seen at the dither pick off for a given dither level, known as the gain of the dither pickoff, can vary significantly between RLGs. Therefore, the same dither control electronics may not provide the same performance from one RLG to another. A manual way to use the same the basic electronics for all RLGS but customize the operation to each gyro for its dither pickoff gain can include using resistor or capacitor divider network to vary the gain of an amplifier producing the dither pickoff that is used to control the motor drive.